Compressors

ABSTRACT

A compressor includes a suction chamber, a crank chamber, and a drive shaft extending through the crank chamber. The drive shaft includes a passage formed therein, and a hole formed therein. For example, the hole may be formed through the drive shaft. The compressor also includes a path communicating between the crank chamber and the suction chamber. Specifically, the path includes the passage and the hole.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates generally to compressors. In particular, the present invention is directed towards compressors having a hole formed through a drive shaft of the compressor for separating a lubricant from a refrigerant.

[0003] 2. Description of Related Art

[0004] Known compressors may be used in an air conditioning system. Specifically, such air conditioning systems include a refrigeration circuit, and the refrigeration circuit may include the compressor. Such known compressors include a swash plate or a cam plate positioned within a crank chamber, and a piston which reciprocates within a cylinder bore. An inclination angle of the plate varies in response to a pressure in the crank chamber, and the inclination angle determines a stroke length of the piston. Specifically, when the pressure in the crank chamber increases, the inclination angle and the stroke length of the piston decrease. Similarly, when the pressure in the crank chamber decreases, the inclination angle and the stroke length of the piston increase. Moreover, when the piston moves away from the suction chamber, the piston draws a refrigerant, e.g., a liquid refrigerant or a refrigerant gas, from the suction chamber into the cylinder bore. Similarly, when the piston moves toward the suction chamber, the piston compresses the refrigerant within the cylinder bore and discharges the compressed refrigerant into a discharge chamber.

[0005] Such known compressors also include a first path which allows refrigerant communication between the crank chamber and the discharge chamber, and a second path which allows refrigerant communication between the crank chamber and the suction chamber. The pressure in the crank chamber increases when the refrigerant flows from the discharge chamber to the crank chamber. The pressure in the crank chamber also increases when the piston compresses the refrigerant, and blow-by gas flows into the crank chamber via a gap formed between the piston and the cylinder bore. Conversely, the pressure in the crank chamber decreases when the refrigerant and the blow-by gas flows from the crank chamber to the suction chamber.

[0006] Moreover, a lubricant, e.g., a lubricating oil, is sealed in the crank chamber for lubricating moving parts of the compressor, e.g., the plate, the piston, and the like. Specifically, when the refrigerant and the blow-by gas flow into the crank chamber, the lubricant is carried along the flow path of the refrigerant and the flow path of the blow-by gas within the crank chamber to lubricate the moving parts of the compressor. Nevertheless, the distribution of the lubricant within the crank chamber is limited to the flow path of the refrigerant and the flow path of the blow-by gas. Moreover, at least a portion of the lubricant is carried by the refrigerant and the blow-by gas into the suction chamber, such that the carried portion of the lubricant enters the refrigeration circuit. When the carried portion of the lubricant enters the refrigeration circuit, the efficiency of the air conditioning system decreases.

SUMMARY OF THE INVENTION

[0007] Therefore, a need has arisen for compressors which overcome these and other shortcomings of the related art. A technical advantage of the present invention is that the amount of lubricant which enters the refrigeration circuit is reduced relative to the amount of lubricant which enters the refrigeration circuit in the known compressors.

[0008] In an embodiment of the present invention, a compressor comprises a suction chamber, a crank chamber, and a drive shaft extending through the crank chamber. The drive shaft comprises a passage formed in the drive shaft, and a hole formed in the drive shaft. For example, the hole may be formed through the drive shaft. The compressor also comprises a path communicating between the crank chamber and the suction chamber. Specifically, the path comprises the passage and the hole.

[0009] Other objects, features, and advantage will be apparent to persons of ordinary skill in the art from the following detailed description of the invention and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] For a more complete understanding of the present invention, the needs satisfied thereby, and the objects, features, and advantages thereof, reference now is made to the following description taken in connection with the accompanying drawings.

[0011]FIG. 1 is a cross-sectional view of a compressor according to an embodiment of the present invention.

[0012]FIG. 2 is a side view of a drive shaft of a compressor according to an embodiment of the present invention.

[0013]FIG. 3 is a partial, cutaway view of the drive shaft of FIG. 2.

[0014]FIG. 4 is a side view of a drive shaft of a compressor according to another embodiment of the present invention.

[0015]FIG. 5 is a partial, cutaway view of the drive shaft of FIG. 4.

[0016]FIG. 6 is a side view of a drive shaft of a compressor according to still another embodiment of the present invention.

[0017]FIG. 7 is a partial, cutaway view of the drive shaft of FIG. 6.

[0018]FIG. 8 is a partial, cutaway view of a drive shaft of a compressor according to yet another embodiment of the present invention.

[0019]FIG. 9 is a partial, cutaway view of a drive shaft of a compressor according to still yet another embodiment of the present invention.

[0020]FIG. 10 is a partial, cutaway view of a drive shaft of a compressor according to a further embodiment of the present invention.

[0021]FIG. 11 is a partial, cutaway view of a drive shaft of a compressor according to still a further embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODJMNTS

[0022] Preferred embodiments of the present invention and their features and advantages may be understood by referring to FIGS. 1-11, like numerals being used for like corresponding parts in the various drawings.

[0023] Referring to FIG. 1, a compressor 100 according to an embodiment of the present invention is depicted. Compressor 100 may comprise a cylinder block 50 and a crankcase 51 fixed to a front end of the cylinder block 50. In an embodiment, crankcase 51 may comprise a boss portion 51 b, and a pulley 56 may be fitted on boss portion 51 b via a radial bearing 57. Pulley 56 may be operationally connected to a driving source (not shown), e.g., an engine of a vehicle, via a belt (not shown). Cylinder block 50 and crankcase 51 may define a crank chamber 41. Cylinder block 50 and crankcase 51 each may have a center hole 50 a and 51 a formed therethrough, respectively. Cylinder block 50 and crankcase 51 also may support a drive shaft 52 via a pair of radial bearings 53 and 54 positioned within center holes 50 a and 51 a, respectively. Drive shaft 52 extends in an axial direction within compressor 100, and a front end 52 a of drive shaft 52 extends through crank chamber 41 and into crankcase 51. First end 52 a of drive shaft 52 may be operationally connected to pulley 56 via a plate spring 58 and a connection member 59. A gap formed between center hole 51 a and drive shaft 52 may be sealed by a seal lip 55. In another embodiment of the present invention, pulley 56 and the belt may include an electromagnetic clutch (not shown), such that first end 52 a of drive shaft 52 may be operationally connected to pulley 56 via the electromagnetic clutch.

[0024] Cylinder block 50 may have a plurality of cylinder bores 60 formed therein, and cylinder bores 60 may extend in an axial direction toward crank chamber 41. In an embodiment, compressor 100 may comprise an odd number of cylinder bores, e.g., seven cylinder bores. Compressor 100 also may comprise a plurality of pistons 62, and each piston 62 may be positioned within a corresponding one of cylinder bores 60, such that each piston 62 reciprocates independently within its corresponding cylinder bore 60. Moreover, a valve plate 61 may be fixed to cylinder block 50 to enclose each piston 62 within its corresponding cylinder bore 60. Valve plate 61 may have a suction port 61 a and a discharge port 61 b formed therethrough, and a cylinder head 63 may be fixed to valve plate 61. A suction chamber 42 and a discharge chamber 43 may be formed within cylinder head 63, and suction chamber 42 and discharge chamber 43 may be in refrigerant communication with cylinder bores 60 via suction port 61 a and discharge port 61 b, respectively. A control valve assembly 64 may be positioned within cylinder head 63. Control valve assembly 64 may be in fluid communication with discharge chamber 43 via a first passage 65 formed in cylinder head 63. Control valve assembly 64 also may be in fluid communication with suction chamber 42 via a second passage 66. Second passage 66 may be formed through cylinder block 50, valve plate 61, and cylinder head 63.

[0025] Compressor 100 also may comprise a rotor 67 mounted on drive shaft 52, and a swash plate 69. Rotor 67 may be positioned within crank chamber 41, and rotates when drive shaft 52 rotates. Crankcase 51 may support rotor 67 via a thrust bearing 68. Rotor 67 may comprise a first arm portion 67 a having an elongated hole 67 b formed therethrough. Swash plate 69 may comprise a second arm portion 69 a, and a pin 69 b. Pin 69 b may be positioned within hole 67 b and is movable within hole 67 b, such that an inclination angle of swash plate 69 may be varied. Compressor 100 also may comprise a plurality of shoe pairs 70, and a peripheral portion of swash plate 69 may be positioned between a first and a second shoe of shoe pair 70. Shoes pairs 70 may be supported by shoe supporters 62 a which are formed integrally with pistons 62, and each shoe 70 may slide on an inner surface of a corresponding one of shoe supporters 62 a. Thus, swash plate 69 may be coupled to pistons 62 via shoes pairs 70. When drive shaft 52 rotates, swash plate 69 also rotates. Moreover, swash plate 69 slides between shoe pairs 70, and pistons 62 reciprocate within their corresponding cylinder bore 60.

[0026] In an embodiment of the present invention, drive shaft 52 may comprise a connection hole 20 formed therethrough, and a drive shaft passage 10 formed therein. Drive shaft passage 10 may extend in the axial direction from a rear end 52 b of drive shaft 52, and the length of drive shaft passage 10 may be less than the length of drive shaft 52, such that drive shaft passage 10 does not reach first end 52 a of drive shaft 52. First passage 52 may intersect with connection hole 20, such that connection hole 20 forms an opening for first passage 52. Drive shaft passage 10 may be in fluid communication with crank chamber 41 via connection hole 20. Drive shaft passage 10 also may in fluid communication with suction chamber 42 via center hole 50 a and a third passage 71. Third passage 71 may be formed through cylinder block 50 and valve plate 61. Moreover, connection hole 20, drive shaft passage 10, center hole 50 a, and third passage 71 may form a path which allows refrigerant communication between crank chamber 41 and suction chamber 42.

[0027] In this embodiment of the present invention, connection hole 20 may be positioned between rotor 67 and swash plate 69. For example, rotor 67 may comprise a front rotor wall 67 d and a rear rotor wall 67 c, swash plate 69 may comprise a front plate wall 69 c and a rear plate wall 69 d, and rear rotor wall 67 c may face front plate wall 69 c. In general, connection hole 20 may be positioned more proximate to rear rotor wall 67 c than to front rotor wall 67 d. For example, connection hole 20 may be positioned between a first location P1 and a second location P2, in which first location P1 corresponds to a location of rear rotor wall 67 c, and second location P2 corresponds to a location of front plate wall 69 c when an inclination angle of swash plate 69 is at a maximum inclination angle. In another example, connection hole 20 may be positioned between second location P2 and a third location P3, in which third location P3 corresponds to a location of rear plate wall 69 d when the inclination angle of swash plate 69 is at the maximum inclination angle. In yet another example, connection hole 20 may be positioned between third location P3 and a fourth location P4, in which fourth location P4 corresponds to a location of front plate wall 69 c when the inclination angle of swash plate 69 is at a minimum inclination angle.

[0028] During compressor operation, the refrigerant generally flows along a first flow path indicated by a first plurality of arrows F1, F2, F5, and F6, and the blow-by gas generally flows along a second flow path indicated by a second plurality of arrows F3, F4, F5, and F6. Specifically, the refrigerant may enter a lower portion of crank chamber 41 via second passage 66, and then may enter drive shaft passage 10 via connection hole 20. Similarly, the blow-by gas may enter an upper portion of crank chamber 41 via a gap formed between cylinder bore 60 and a corresponding one of pistons 62, and then may enter drive shaft passage 10 via connection hole 20. The refrigerant and the blow-by gas may combine within drive shaft passage 10, and then may flow into suction chamber 42 via drive shaft passage 10, center hole 50 a, and third passage 71.

[0029] When the refrigerant or the blow-by gas flows within crank chamber 41, a lubricant sealed within crank chamber 41 also may flow with the refrigerant or the blow-by gas toward connection hole 20. When the lubricant is proximate to connection hole 20, a first portion of the lubricant may flow with the refrigerant or the blow-by gas into drive shaft passage 10. Nevertheless, a second portion of the lubricant also may contact the outer surface of drive shaft 52, and separate from the refrigerant or the blow-by gas. Moreover, because drive shaft 52 rotates during compressor operation, the centrifugal force generated by drive shaft 52 causes the separated lubricant to scatter along the outer surface of drive shaft 52. As such, the movement of the separated lubricant may be independent from the flow of the refrigerant and the blow-by gas within crank chamber 41, and the moving components of compressor 100 may be more sufficiently lubricated than the moving components in known compressors. Moreover, because the second portion of the lubricant may not enter suction chamber 42, the efficiency of an air conditioning system comprising compressor 100 may be greater than the efficiency of known air conditioning systems.

[0030] Referring to FIGS. 2 and 3, in an embodiment, connecting hole 20 may be formed perpendicular to drive shaft passage 10, and may have a cylindrical shape. Connecting hole 20 also may be formed through drive shaft 52, or as shown in FIG. 11, connecting hole 20 may be formed within drive shaft 52. Referring to FIGS. 4 and 5, in another embodiment, connecting hole 20 may be slanted relative to drive shaft passage 10 (as shown by reference numeral 21). Specifically, slanting connecting hole 20 relative to drive shaft passage 10 may alter the direction in which the second portion of the lubricant scatters. referring to FIGS. 6 and 7, in yet another embodiment, connecting hole 20 may have a conical shape (as shown by reference numeral 22), such that a diameter of connecting hole 20 may decrease between the outside of drive shaft 52 and a center of drive shaft 52. Referring to FIGS. 8-10, in still another embodiment, at least a portion of a pipe 30 may be positioned within connection hole 20. Pipe 20 may extend a length of connecting hole 20, such that an amount of the lubricant which separates from the refrigerant may increase. For example, a first portion of pipe 30 may be cylindrical shaped and positioned within connection hole 20. Moreover, a second portion of pipe 30 may be positioned outside connection hole 20. The second portion of pipe 30 may be cylindrical shaped, conical shaped, or the like. The second portion of pipe 30 also may be substantially perpendicular to drive shaft passage 10, or may be slanted relative to drive shaft passage 10.

[0031] While the invention has been described in connection with preferred embodiments, it will be understood by those skilled in the art that variations and modifications of the preferred embodiments described above may be made without departing from the scope of the invention. Other embodiments will be apparent to those skilled in the art from a consideration of the specification or from a practice of the invention disclosed herein. It is intended that the specification and the described examples are consider exemplary only, with the true scope of the invention indicated by the following claims. 

What is claimed is:
 1. A compressor comprising: a suction chamber; a crank chamber; a drive shaft extending through the crank chamber, wherein the drive shaft comprises: a passage formed in the drive shaft; and a hole formed in the drive shaft; and a path communicating between the crank chamber and the suction chamber, wherein the path comprises the passage and the hole.
 2. The compressor of claim 1, further comprising: a swash plate rotatably mounted on the drive shaft; and a rotor fixedly mounted on the drive shaft, wherein the rotor is operationally connected to the swash plate.
 3. The compressor of claim 1, wherein the rotor comprises: a front rotor wall; and a rear rotor wall, wherein the front rotor wall is a first predetermined distance from the swash plate, the rear rotor wall is a second predetermined distance from the swash plate, and the first predetermined distance is greater than the second predetermined distance.
 4. The compressor of claim 3, wherein a center of the hole is a third predetermined distance from the front rotor wall, the center of the hole is a fourth predetermined distance from the rear rotor wall, and the third predetermined distance is greater than the fourth predetermined distance.
 5. The compressor of claim 2, wherein the rotor comprises: a front rotor wall; and a rear rotor wall, wherein the swash plate comprises: a front plate wall; and a rear plate wall, wherein: the font rotor wall is a first distance from the front plate wall; the front rotor wall is a second distance from the rear plate wall; the rear rotor wall is a third distance from the front plate wall the rear rotor wall is a fourth distance from the rear plate wall; the first distance is greater than the third distance; and the second distance is greater than the fourth distance.
 6. The compressor of claim 5, wherein when an inclination angle of the swash plate is equal to a maximum inclination angle, the hole is positioned between the rear rotor wall and the front plate wall.
 7. The compressor of claim 6, wherein the hole is substantially cylindrical shaped.
 8. The compressor of claim 6, wherein the hole is substantially conical shaped.
 9. The compressor of claim 6, wherein the hole is perpendicular to the passage.
 10. The compressor of claim 6, wherein the hole is slanted relative to the passage.
 11. The compressor of claim 6, further comprising a extension pipe, wherein a first portion of the extension pipe is positioned within the bole, and a second portion of the extension pipe is positioned outside the hole.
 12. The compressor of claim 11, wherein the first portion is substantially cylindrical shaped.
 13. The compressor of claim 11, wherein the first portion is perpendicular to the passage.
 14. The compressor of claim 11, wherein the first portion is slanted relative to the passage.
 15. The compressor of claim 11, wherein the second portion is substantially cylindrical shaped.
 16. The compressor of claim 11, wherein the second portion is substantially conical shaped.
 17. The compressor of claim 11, wherein the second portion is perpendicular to the passage.
 18. The compressor of claim 11, wherein the second portion is slanted relative to the passage
 19. The compressor of claim 1, wherein the hole is formed through the drive shaft.
 20. The compressor of claim 1, wherein a center of the hole comprises an opening of the passage. 